drm/amd/display: Match actual state during S3 resume.

During system suspend, we:

1. Cache a duplicate of the current DRM atomic state, which calls hooks
   to duplicate our internal states.
2. Call hooks to disable all functionalities.
3. System suspended.

During resume, we attempt to restore the cached state. However, our
interal states are now stale, since step 1 was done before step 2.
i.e. our cached state does not reflect the disabled nature of things.

This change resolves that by destroying all relevant states to reflect
the actual state during resume.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>